Springy Tires For Mars
What is it? NASA engineers developed a puncture-proof tire made of a special woven-mesh metal that immediately springs back into shape while moving over jagged or uneven surfaces. Space-grade tires used since the 1960s haven’t coped well with the unforgiving surface of Mars, but engineers have high hopes for their new tire, which eventually could be a boon to Earth drivers as well.
Why does it matter? The aluminum tires used on the nuclear-powered Mars Curiosity robot started shredding after just a year roving over the sandy, rocky surface of the red planet. Amazon isn’t delivering replacements just yet, so NASA needed a durable tire that was tough enough to withstand the harsh conditions, including daily temperature swings from minus 200 degrees to 70 degrees Fahrenheit, and wouldn’t tear or become deformed. Engineers worked with various woven metals, similar to what’s used today, but couldn’t figure out how to prevent the inevitable dents that accumulate over the expected 10-year life of the tire. A chance encounter between two engineers led them to collaborate using a “shape-memory alloy” — a super-elastic metal that pops back into place, even after intense strain.
How does it work? The nickel-titanium (NiTi) alloy engineers settled on has about 30 times more elasticity than the aluminum tires now used on Mars. That extra elasticity means tires made from it can carry nearly 10 times the weight, grip better on rocks and sand and climb slopes about 23 percent steeper. "We can actually deform this all the way down to the axle and have it return to shape, which we could never even contemplate in a conventional-metal system," said NASA materials scientist Santo Padula. The elasticity comes from the alloy’s crystal structure, which is composed of stretchy bonds at the molecular level. Engineers are working with Goodyear to develop a tire for Earth use, so off-roaders can be as high-tech as the Mars rovers.
What is it? The first U.S. baby born to a woman with a transplanted uterus was delivered this month at Baylor University Medical Center in Dallas. The U.S. baby was the first born from a transplant outside Sweden, where the procedure has led to eight births since 2014.
Why does it matter? The procedure opens up new possibilities for women with certain infertilities, including those born without a uterus. It’s also one of the first instances of transplant surgery being used as a temporary measure. Dr. Liza Johannesson, a uterus transplant surgeon at Baylor who also worked in Sweden, noted the significance of the procedure’s success in a new hospital under a new team. “To make the field grow and expand and have the procedure come out to more women, it has to be reproduced,” she told The New York Times.
How does it work? Surgeons implant a uterus from a volunteer or cadaver into a woman who was born without one, or whose uterus was damaged by illness or trauma. In-vitro fertilized eggs then are transferred to the woman’s new uterus. Once she delivers a baby, doctors remove the uterus so that she can stop taking immune-suppressing anti-rejection drugs, which elevate her risk for infection, cancer, heart disease and bone marrow loss. So far, 10 women have been involved in Baylor’s clinical trial. Eight have received transplants, including the new mother. Four transplants failed, one recipient is trying to conceive, and another currently is pregnant.
Artificial Heart Patch
What is it? Duke University scientists created an artificial heart muscle that can be patched over dead tissue in rats and mice, and hopefully one day in humans who have suffered heart attacks.
Why does it matter? Dead heart muscle won’t regenerate, and scar tissue left after a heart attack can’t contract or send electrical signals, both of which are necessary for proper heart function. Some 12 million people worldwide suffer from the resulting heart failure. Duke biomedical engineers think doctors could one day implant their artificial heart tissue over existing dead muscle, restoring its ability to beat and carry electrical currents.
How does it work? The patch cells are grown from human stem cells in a jelly-like culture. Various types of muscle cells are needed for the patch, including cells responsible for muscle contraction, cells that provide the heart’s structural framework, and cells that form blood vessels. The patches also secrete enzymes and growth hormones, possibly helping damaged tissue recover. The Duke team spent years determining the right combination of cells, hormones, nutrients and culture conditions to grow patches large enough to cover the dead parts of the heart muscle. They discovered along the way that gently rocking the cells improved nutrient delivery by bathing the cells. That led to bigger cells and therefore larger patches, up to 16 square centimeters and five to eight cells thick. The patches take about five weeks to grow to adult muscle strength, and they have been shown to work on rat and mouse hearts. However, they’ll need to be significantly thicker (roughly 1.1 centimeters) to work in humans. The team’s findings appear in Nature Communications.
Biological Crystals Power Music
What is it? Scientists at the University of Limerick in Ireland discovered a cheap, environmentally friendly way to power devices such as mobile phone speakers and car sensors using energy produced by glycine, an amino acid.
Why does it matter? Glycine is the simplest amino acid. As a naturally occurring molecule, it can be produced commercially at less than 1 percent the cost of synthetic compounds used to generate electricity in cars, phones and remote controls. Plus, glycine has no toxic byproducts such as lead or lithium, making it a sustainable energy source.
How does it work? Glycine, when tapped or squeezed, generates electricity. Limerick researchers grew long, narrow crystals of glycine in alcohol and produced enough energy to power simple electronic devices just by tapping the crystals. Scientists started by using computer models to predict the electrical response of a wide range of crystals. Glycine “was off the charts,” said Sarah Guerin, lead author of the study, which appears in Nature Materials. The predictive computer models also helped determine what kinds of crystals to grow (long and narrow) and where best to cut and press those crystals to generate electricity. "It is really exciting that such a tiny molecule can generate so much electricity," said Guerin.
Stretchable Bacteria Batteries
What is it? Scientists at Binghamton University, State University of New York, developed a stretchy, flexible bacteria-powered bio-battery made of fabric that potentially could be integrated into wearable electronics, or “smart clothes.”
Why does it matter? Researchers hope that one day the small, microbial fuel cells will replace oil, coal or even solar energy as a long-lasting, universally available and inexpensive renewable energy source that can generate power in any conditions. In the meantime, the textile-based bio-batteries are a platform for wearable technology because they have proven to be stable electricity generators despite repeated stretching and twisting. That flexibility means they easily can be incorporated into clothing to collect real-time information about the wearer or surrounding environment.
How does it work? Bacteria in microbial fuel cells generate electricity when they eat. As the bacteria break down complex organic molecules, energy is released and can be tapped to generate power. Roughly 16 of the microbial fuel cells connected together can power a light-emitting diode (LED). Researchers think sweat from the human body may be a potential food source to support the bacteria, which would make maintaining them simple and cheap, and allow them to generate power almost indefinitely. The team’s paper, "Flexible and Stretchable Biobatteries: Monolithic Integration of Membrane-Free Microbial Fuel Cells in a Single Textile Layer," appears in Advanced Energy Materials.